Development

Shanghai Minwei launches first human trial of ActRIIA/B antibody for obesity

Shanghai Minwei launches first human trial of ActRIIA/B antibody for obesity

Shanghai Minwei Biotechnology Co., Ltd. has registered a Phase I first-in-human clinical trial of MWN110, a monoclonal antibody targeting activin receptors ActRIIA and ActRIIB, in healthy volunteers and people with overweight or obesity. The study marks the first human trial of the asset, which Minwei, a subsidiary of Lepu Medical Technology (SHE: 300003), said was developed in-house and is covered by intellectual property rights held by the company.

The study (NCT07779980) is a randomized, double-blind, placebo-controlled single- and multiple-ascending-dose trial designed to enroll approximately 103 participants aged 18 to 65 years across sites in China. Part 1 includes eight single-dose cohorts ranging from 15 mg to 1,200 mg in healthy volunteers, while Part 2 evaluates multiple doses in participants with overweight or obesity, including two cohorts dosed weekly for five weeks and one cohort receiving two doses four weeks apart. Pharmacodynamic endpoints include changes in body weight, body mass index, waist circumference, muscle mass, body fat percentage, visceral and subcutaneous fat, and bone mineral density, indicating that the study will assess body composition as well as overall weight.

ActRIIA and ActRIIB mediate signaling by members of the TGF-β superfamily, including myostatin and activins, which regulate skeletal muscle mass and other physiological processes. Inhibition of this pathway has emerged as a potential approach to altering body composition by increasing or preserving lean mass while reducing fat mass. That profile could complement incretin-based obesity therapies, which produce substantial weight loss but can also result in loss of lean mass alongside fat.

Bimagrumab, an antibody targeting ActRIIA and ActRIIB, has provided clinical validation for the approach. Originally developed by Novartis and later acquired by Versanis Bio, which Eli Lilly acquired in 2023, bimagrumab has demonstrated reductions in fat mass alongside increases in lean mass in clinical studies. Minwei has made a patent filing (WO2025068454A1) that describes antibodies targeting ActRIIA and ActRIIB, but the firm has not disclosed comparative clinical data for MWN110, which is only now entering human testing.

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The trial design reinforces the focus on body composition. Recent use of GLP-1 receptor agonists and other weight-loss drugs is excluded, while restrictions on strenuous resistance training are intended to reduce factors that could confound measurements of muscle and fat. Ophthalmic assessments are also included in the safety monitoring, although the significance of those examinations for MWN110 cannot be established before clinical safety data become available.

MWN110 adds a mechanistically distinct program to Minwei's metabolic pipeline. The company's MWN101, a glucagon receptor/GIP receptor dual agonist, has undergone Phase II development, while MWN105, a GLP-1/GIP/FGF21 triple agonist, was out-licensed to Denmark-based Sidera Bio in a deal potentially worth approximately USD 1.045 billion in milestone payments, with Minwei retaining a 9.99% equity stake in Sidera. Unlike those incretin-related programs, MWN110 is aimed directly at pathways regulating muscle and body composition, potentially positioning it as a complementary approach to appetite-driven weight-loss therapies.

The Phase I study has an estimated start date of August 26, 2026, with primary completion expected in August 2027. Beyond initial safety and pharmacokinetics, the key early signal will be whether ActRIIA/B blockade with MWN110 produces measurable changes in muscle and fat compartments sufficient to support further development as a body composition-focused obesity therapy.


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